The present invention relates to a hydrokinetic coupling apparatus for a motor vehicle.
Such a hydrokinetic coupling apparatus is described, for example, in the document FR-A-2.738.891.
In this document, the apparatus includes an input element in the form of a casing equipped with a wall of overall transverse orientation, and an output element comprising a turbine-wheel fitment housed within the casing. The turbine wheel belongs to a hydrokinetic converter which consists of three elements fitted with vanes, with no mechanical link between them. The turbine wheel is integral with a hub linked in rotation to a receiving shaft, or driven shaft, which is itself linked to the input shaft of the gearbox of the vehicle, and it works together with an impeller wheel which is linked in rotation to the casing which is linked in rotation to the driving shaft driven by the combustion engine, a reactor being interposed axially between the turbine wheel and the impeller wheel, being mounted so as to rotate on the driven shaft with the interposition of a free wheel which allows rotation of the reactor in the engine direction, but prevents it in the opposite direction.
The invention thus relates, more particularly, to a hydrokinetic coupling apparatus, especially for a motor vehicle, including a casing suitable for being linked in rotation to a driving shaft, a front turbine wheel housed within the casing, integral with a hub, suitable for being linked in rotation to a driven shaft and which is driven, by virtue of the circulation of the fluid contained in the casing, by a rear impeller wheel, linked in rotation to the casing, with the intervention of a reactor, arranged axially between the front turbine wheel and rear impeller wheel, including a reactor body the central, radially inner, part of which is linked in rotation to the coaxial driven shaft which passes through it, with the interposition of a free wheel.
In a known way, the free wheel includes:
an outer ring linked in rotation to the central part of the reactor body;
intermediate blocking elements, which interact with an outer track of the outer ring and with an inner track of an inner ring of the free wheel which is linked in rotation to a fixed sleeve;
and at least one affixed lateral flange, in the general shape of a washer of transverse orientation, perpendicular to the axis of the free wheel, which is immobilised axially with respect to the central part of the reactor body and which extends radially inwards beyond the outer ring in order to retain the intermediate elements axially, in at least one direction.
In order to enhance the link between the inner ring of the free wheel and the reactor body, and especially in such a way as to provide a link in translation of the inner ring of the free wheel with respect to the reactor body and to enhance the rotational guidance of the free wheel with respect to the reactor body, a hydrokinetic coupling apparatus of the above-mentioned type has already been proposed, in which the said at least one lateral flange extends radially inwards in such a way as to interact, via its inner periphery, with a facing portion of the inner ring so as to link the reactor body in axial translation with the inner ring and/or to guide the reactor body in rotation with respect to the inner ring.
Such a design is described and represented in the document EP-A1-0.549.824, for example.
In order to reduce the number of components and to simplify their assembly, the invention proposes an apparatus of the above-mentioned type, characterised in that, for the axial retention of the flange, at least one, generally rod-shaped, element is provided, which passes axially, at least partly, through the outer ring of the free wheel or the body of the reactor, or which extends axially within the free wheel.
The invention proposes various embodiments which especially make it possible to reduce the number of machining operations to be carried out on the reactor body, to facilitate the fitting of the subassembly consisting of the reactor with its free wheel, to reduce the axial bulk of this subassembly, and more generally to simplify the design of the reactor by limiting the number of components in it and the number of types of components so as to produce a range of reactors while reducing the costs of manufacture and of assembly of this subassembly.
According to other characteristics of the invention:
the inner ring is traversed axially by the fixed sleeve, to which it is linked in rotation
the inner ring consists of a portion of the fixed sleeve for one design according to the invention of a free wheel, called free wheel without inner ring;
the free wheel includes only a single lateral flange, and the central part of the reactor includes a lateral cheek of transverse orientation perpendicular to the axis of the free wheel, opposite the said single flange, which, with the latter, axially delimits a cavity in which are arranged the outer ring and the intermediate elements;
the free wheel includes another affixed lateral flange, in the general shape of a washer, of transverse orientation perpendicular to the axis of the free wheel, which is immobilised axially with respect to the central part of the reactor body, which extends radially inwards beyond the outer ring so as to retain the intermediate elements axially, in at least one direction, which is opposite the said at least one lateral flange, and which, with the latter, axially delimits a cavity in which are arranged the outer ring and the intermediate elements;
the said other lateral flange extends radially inwards so as to interact, via its inner periphery, with a facing portion of the inner ring so as to link the reactor body in axial translation with the inner ring and/or to guide the reactor body in rotation with respect to the inner ring;
the free wheel includes at least one outer cage which axially retains the intermediate elements, and the lateral flange is an element independent of the outer ring and of the outer cage;
the free wheel includes at least one outer cage which axially retains the intermediate elements, and the lateral flange is an element produced in a single piece with the outer cage;
the lateral flange is linked in rotation to the central part of the reactor;
the outer periphery of the lateral flange includes at least one rotational drive spigot which extends, especially radially outwards or axially, and which is received into a complementary cavity of the central part of the reactor which is open axially towards the flange;
the lateral flange is linked in rotation to the outer ring;
the lateral flange is retained axially with respect to the central part of the reactor body;
the lateral flange is retained axially by elastically deformable hooks received into complementary recesses;
the rod-shaped element is produced in the form of an independent component, especially a rivet;
the rivet-shaped element is produced in a single piece with an outer cage of the free wheel;
characterised in that the rivet-shaped element is produced in a single piece with a lateral flange;
the flange includes a transverse face which constitutes a bearing track for an axial, needle-type thrust bearing, interposed between the reactor and the turbine wheel, or between the reactor and the impeller wheel.